The present invention relates to the technical field of anastomosis devices for joining together hollow lumens or viscera, the devices being suitable for being deployed at the surfaces of superposed adjacent lumens.
Surgical anastomosis is surgically butt joining two ducts by manual suturing or by stapling. Suturing is performed with thread that is referred to as resorbable since it disappears by itself over time inside the organism. Such sutures are used in digestive surgery (relating to surgery on the stomach, the duodenum, the small intestine, the colon, or the anus), and in bariatric surgery, and also in urological surgery with regard to the urinary tract. Sometimes, surgical anastomoses are performed using a non-resorbable suture, in particular for anastomosis of blood vessels, in particular of the arteries.
Anastomosis in the field of digestive surgery is used to re-establish continuity of the digestive tube. The digestive tube, made up of the duodenum, the small intestine, and the colon, may become blocked by a neoplasm. It is thus necessary to re-establish the flow of food by resecting the blocked portion of the digestive tube, and then butt joining the two free ends of the digestive tube. Such butt joining is achieved by means of a circular stapler, or manually by sutures.
The purpose of anastomosis in the field of bariatric surgery is for surgically treating obesity. One of the surgical techniques is biliopancreatic diversion or the Scopinaro operation. That surgical technique consists in particular in making a pouch by removing a large portion of the stomach, and by connecting it, via an anastomosis, to the last portion of the small intestine, thus taking the major portion of the intestine out of circuit. Consumed food is thus digested only very little.
Various types of digestive anastomoses are as follows:                an eso-gastric anastomosis is performed between the esophagus and the stomach;        a gastro-jejunal anastomosis is performed between the stomach and the jejunum;        a duodeno-jejunal anastomosis is performed between the duodenum and the jejunum;        an ileocolic anastomosis is performed between the ileun and the colon;        a colo-colic anastomosis is performed between two portions of the colon; and        an ileo-rectal anastomosis is performed between the ileun and the rectum.        
Implantable devices making it possible to form gastro-intestinal anastomoses via the transesophageal endoscopic approach initially lead to ischemic necrosis of the tissues by compression, which necrotic portion then falls into the small intestine after maturation of the necrosis. Maturation of the necrosis may be defined as the moment from which the necrotic tissues may be separated easily from the vascularized tissues.
Documents EP 1 790 297 A1 and WO 03/000142 disclose anastomosis devices comprising a tube constituted by shape-memory wires that, as can be seen in the structure shown in FIG. 2 of WO 03/000142 and in FIG. 8 of EP 1 790 297 A1, are interwoven and shaped either by braiding, or manually by interweaving the wires on a support including nails.
In operation, the devices of annular shape, as can be seen for example in FIG. 5C of EP 1 790 297 A1, or in FIG. 3B of WO 03/000142, present petals that are interwoven and that project along their outer periphery.
The gastric and intestinal tissues positioned between the petals necrotize by compression, then the necrotic portion, together with the device, falls into the digestive system so as to leave in place an opening, commonly referred to as an anastomosis.
Just after being implanted and before the tissues have healed, the devices may slide from their implantation site in such a manner that physical connection between the stomach and the small intestine is thus no longer guaranteed. Gastric and intestinal secretions then flow into the peritoneal cavity. The patient may then die of peritonitis or of a general infection (septicemia).
After several months of implantation and following necrosis of the tissues that are superposed and positioned between the petals, the devices are designed to fall into the small intestine. As a result, they are potentially dangerous for the patient. Specifically, once they have fallen into the small intestine, the devices may block the digestive system, generating an occlusion of the intestinal duct and then causing an intestinal perforation.
Furthermore, gastric acid can corrode the titanium-nickel alloys used in the devices and cause wires to break at multiple locations, after an implantation duration that is longer than 120 days. The sharp ends of the broken wires may perforate the organs or they may become embedded in the intestinal wall. When the devices fall into the intestine, the ends of the wires may become embedded in the wall of the intestine and may become permanently attached, thereby creating an intestinal occlusion. The consequences of such an occlusion may be fatal.
Furthermore, an anastomosis made with that technique does not make it possible to create a long-lasting opening between the stomach and the small intestine. The anastomosis that is created re-closes, since the tissues that are formed are of fibrotic origin.
In the devices described in documents EP 1 790 297 and WO 03/000142, the compression force depends on the thickness of the held-together gastric and intestinal walls, since the compression force provided by the petals at the outer periphery of said devices is uniform.
Necrosis thus matures quickly if the walls are thick. However, necrosis matures more slowly if the walls are thinner.
This observation implies that that type of anastomosis device is not designed to be removed in reliable manner from any patient. Specifically, if the device is put in a patient having gastric and intestinal walls that are thin, and the gastroenterologist wishes to remove the implant at 90 days, there exists a great risk that during surgery, consisting in removing the anastomosis device in order to release the anastomosis that has been created, necrosis is not mature and the surgeon is unable to remove said device. If the same device is put in a patient having gastric and intestinal walls that are thicker in combination, and the gastroenterologist wishes to remove the implant also at 90 days, there thus exists a risk that necrosis has already matured and that the device has fallen into the digestive system.
Another drawback of such anastomosis devices is that they change length little when they pass from their rest and thus deployed position to their compressed position in an insertion catheter. As described below in the present text, the comparative change in length measured on the anastomosis device between its rest position and position forced into an insertion catheter, lies in the range 20% to 70%. Furthermore, in their compressed position in said insertion catheter, the devices measure only 2 centimeters (cm) or 3 cm, which gives the gastroenterologist only very little margin for maneuver when the device leaves the insertion catheter so as to be put into place on the anatomic walls that are to be brought together.
Those devices thus cannot be put into place on the implantation site in a manner that is accurate, reliable, and reproducible.
The anastomosis device of the present invention makes it possible to control necrosis of the combined anatomic walls, such that the surgeon can remove the implant at 90 days of implantation, and such that necrosis is mature.
Furthermore, the anastomosis device of the present invention makes it possible to secure the gastro-intestinal connection immediately after implantation. Said device is then removed after a determined implantation period, which may be about 90 days, so as to enable the intestinal mucosa go back into place, and so as to leave a long-lasting anastomosis in place.
Document WO 2012/175847 A1 discloses an anastomosis device comprising a knitted main tubular body having top and bottom ends that are folded over in such as manner as to form two bearing surfaces that come to pinch together the anatomic walls that are to be brought together.
That type of device does not enable the compression that is exerted on the anatomic walls that are to be brought together and necrotized to be controlled accurately and differently such that, like the above-described prior-art devices, necrosis is not properly controlled. Thus, there exists a risk of the device falling into the digestive system, leading to the above-mentioned problems.